Tap and die.



NiTEo STATES ATENT OFFICE.

FERDINAND EHMKE, OF READING, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TODANIEL K. BIEHL, OF SAME PLACE.

TAP AND-DIE.

SPECIFICATION forming part of Letters Patent No. 662,064, dated November20, 1900.

Application filed Janilary 4,1900. Serial No. 317. (N model.) I

To all whmn it WI/(Ly concern: Be it known that I, FERDINAND EHMKE, asubject of the Emperor of Germany, and a resident of Reading, in thecounty of Berks and State of Pennsylvania, have invented certain new anduseful Improvements in Taps and Dies, of which the following is aspecification.

The object of my invention is to provide a tap or die which will becapable of cutting equally well either a right or left hand doublethread. It is fully described in connection with the accompanyingdrawings, and the novel features are specifically pointed out 1 in theclaims.

Figure l is a transverse section of a tap embodying my invention, takenon the linear :rof Fig. 2 or Fig. 3. Figs. 2 and 3 are elevations of thesame from two different points of View.

Fig. is a sectional view of a corresponding die embodying my invention.

The general form of the tap or die may be as usual, my inventionrelating exclusively to the arrangeu'ient of the cutting-teeth. The

2 form of these teeth I) is similar to that partially described inUnited States Patent No. 310,462, each tapering radially outward to anapex 1), toward which the longitudinal sides b b and the transversesides 5' b converge,

0 and the latter lying perpendicularly across the axis of the tap andbeing reduced in eX- tent by the longitudinal concaving indicated at dcl, so that they Will not prevent the turning of the tap in eitherdirection. In the 3 5 drawings these cutting-teeth are arranged in fourequally-spaced longitudinal rows, of which rows each diagonally oppositetwo form a pair having their teeth in line or lying in parallel planes 1l and 2 2 perpendicular to 40 the axis of the tap. The other pair ofteeth have their roots instead of their apices lying in these planes 1 1and 2 2, as indicated in Fig. 2, so that their apices are in planesmidway between said planes 1 1 and 2 2. This same arrangement of thecutting-teeth applies to die E, as indicated in Fig. 4.

In forming a tap with the cutting-teeth arranged as described, so as toeffect the object of my invention, I out each row of teeth separately,as in a milling-machine, properly 5o setting the milling-tool for eachrow, instead of cutting a screw-thread as can be done with an ordinarytap.

In using my improved tap or die it is merely inserted in the drilledhole and turned right or left, as desired. The teeth in each pair ofrows then cut a thread, thus jointly cutting a double thread at eachturn of the tap.

What I claim is- 1. A, tap or die for cutting either right or left handdouble threads, having two diametrically opposite rows of pyramidalteeth for each thread,the side faces of which teeth are at right anglesto an axial plane passing through their summits.

2. A tap or die for cutting either right or left hand double threadshaving four equallyspaced rows of pyramidal teeth, with the apices ofthe one pair of teeth in diametrically opposite rows and the bases ofthe teeth in the other rows arranged in the same planes which areperpendicular to the axis of the tap or die, the side faces of the teethbeing at right angles to an axial plane passing through their summits.

Signed by me at Reading, Pennsylvania, this 28th day of December, 1899.

FERDINAND EHMKE.

Witnesses:

W. G. STEWART, WooD M. SCHWARTZ, Jr.

